The interaction of airstream and topography is the main factor governing rainfall in Tasmania. Consequently, the annual rainfall varies markedly across the state, averaging less than 600 mm in the Midlands but over 3,500 mm in some part of the mountainous west. The highest rainfalls occur in remote, unpopulated regions.

While Tasmania experiences a generally reliable rainfall, there are periods when rainfall is significantly below or above the average. These are mainly due to changes to the broad meteorological and oceanographic situation, which affects the number of rain bearing systems over the state. Rainfall is less predictable over the eastern half of the state than in the west.

The highest accumulated rainfall recorded in a calendar year is 4,504 mm at Lake Margaret Dam, in the highlands of the West Coast, in 1948.

The greatest number of rain days recorded in a year is 314 at Waratah in the North-west in 1955, which is also a record for Australia.

The highest rainfall recorded in 24 hours between successive 9 am readings is 352 mm at Cullenswood (in the north-east highlands), on 22 March 1974.

To display maps showing the average annual or monthly rainfall and minimum and maximum temperatures in Tasmania and Australia click on the following link and then enter your selection in the search fields: